This invention generally relates to the treatment of a totally or near totally occluded body lumen and particularly to a catheter for such treatment of blood vessels, e.g. coronary and peripheral arteries.
There are presently several treatment modalities for stenotic or occluded arteries, including balloon and laser angioplasty, atherectomy, by-pass surgery and the like. While each of these treatments has its advantages, each also has its advantages. For example, balloon angioplasty has been found to be highly successful in a wide variety of stenoses, both coronary and peripheral arteries, but there are some stenoses which are too tough to be effectively dilated by an inflatable balloon. Similarly, directional atherectomy has been found to be very successful in soft to medium hardness plaque but is found to be relatively ineffective in very hard, highly calcified plaques.
Laser treatments, hot or cold, and other hot-tipped or heated balloon catheters have also been found to be successful in some stenoses, but the restenosis rate has been disappointingly high. Additionally, the high temperatures frequently developed by some of these devices can damage the arterial lining and can also cause considerable pain.
By-pass surgery has likewise been found to be successful in many instances but such surgery involves a traumatic intrusion into the patient's body and can debilitate the patient for an extended period, even if the treatment is successful.
Ultrasonic ablation of stenotic buildup in peripheral arteries have also been suggested by Don Michael et al. in U.S. Pat. No. 4,870,953. While the ultrasonic treatment has been found to be effective, particularly with highly calcified plaque, the procedure tends to leave a substantial amount of residual blockage.
Total or near total occlusions have presented a particularly difficult problem because most treatment devices which involve intravascular delivery, such as angioplasty, atherectomy and the like, require the treatment device to be advanced into the stenotic region before the treatment can be initiated. Intravascular devices have been introduced having means on their distal ends for removing occluding material to form a channel therein. However, it has been found that very frequently when these devices were advanced through a totally or near totally occluded body lumen the means for removing occluding material on the distal ends of these devices would pass through the wall of the body lumen or otherwise cause damage thereto because the operator would not know where the devices were positioned within the body lumen with respect to the wall defining the body lumen.
What has been needed and has been heretofore unavailable is a treatment system for totally or near totally occluded body lumens, particularly coronary arteries, which can be used to remove or ablate occluding material to recanalize such occluded body lumens with little risk of penetrating or damaging the wall of the body lumen. The present invention satisfies these and other needs.